From d820447212e616093941f45775b52bd4afc86cf0 Mon Sep 17 00:00:00 2001 From: Teresa Johnson Date: Thu, 9 Mar 2017 00:19:49 +0000 Subject: Perform symbol binding for .symver versioned symbols Summary: In a .symver assembler directive like: .symver name, name2@@nodename "name2@@nodename" should get the same symbol binding as "name". While the ELF object writer is updating the symbol binding for .symver aliases before emitting the object file, not doing so when the module inline assembly is handled by the RecordStreamer is causing the wrong behavior in *LTO mode. E.g. when "name" is global, "name2@@nodename" must also be marked as global. Otherwise, the symbol is skipped when iterating over the LTO InputFile symbols (InputFile::Symbol::shouldSkip). So, for example, when performing any *LTO via the gold-plugin, the versioned symbol definition is not recorded by the plugin and passed back to the linker. If the object was in an archive, and there were no other symbols needed from that object, the object would not be included in the final link and references to the versioned symbol are undefined. The llvm-lto2 tests added will give an error about an unused symbol resolution without the fix. Reviewers: rafael, pcc Reviewed By: pcc Subscribers: mehdi_amini, llvm-commits Differential Revision: https://reviews.llvm.org/D30485 llvm-svn: 297332 --- llvm/lib/MC/MCStreamer.cpp | 2 ++ 1 file changed, 2 insertions(+) (limited to 'llvm/lib/MC/MCStreamer.cpp') diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp index 860c1bd6d87..b9c01c66f31 100644 --- a/llvm/lib/MC/MCStreamer.cpp +++ b/llvm/lib/MC/MCStreamer.cpp @@ -821,6 +821,8 @@ void MCStreamer::EmitCOFFSymbolType(int Type) { llvm_unreachable("this directive only supported on COFF targets"); } void MCStreamer::emitELFSize(MCSymbol *Symbol, const MCExpr *Value) {} +void MCStreamer::emitELFSymverDirective(MCSymbol *Alias, + const MCSymbol *Aliasee) {} void MCStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size, unsigned ByteAlignment) {} void MCStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol, -- cgit v1.2.3